CVE-2026-27944 CRITICAL

CVE-2026-27944: Nginx UI: Unauthenticated Backup Download with Encryption Key Disclosure

Vendor 0Xjacky
Product nginx-ui
Weakness CWE-311 · Missing encryption
Published March 5, 2026
Last update March 19, 2026

CVSS base score

9.8/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

What the vulnerability does

Description

Nginx UI is a web user interface for the Nginx web server. Prior to version 2.3.3, the /api/backup endpoint is accessible without authentication and discloses the encryption keys required to decrypt the backup in the X-Backup-Security response header. This allows an unauthenticated attacker to download a full system backup containing sensitive data (user credentials, session tokens, SSL private keys, Nginx configurations) and decrypt it immediately. This issue has been patched in version 2.3.3.

Key dates

Disclosure timeline

March 5, 2026 CVE published
March 19, 2026 Record updated